Command System

Myotus uses an annotation-driven command pipeline in 1.20.1. The system is intentionally small, but it is fully source-backed and already powers /myotus mods.

Registration flow

Command registration starts in init/MyotusCommand on RegisterCommandsEvent.

At startup, Myotus:

1. scans mod file annotation metadata for classes marked with @MyoCommand
2. loads those classes by reflection
3. selects root nodes where parent() == void.class
4. recursively attaches subcommands whose parent() points at the current command class

This means command discovery is not hardcoded to a manual list. If the annotation is present and the class is loadable, it can be picked up automatically.

Core annotations

@MyoCommand

Marks a class as a command node.

@MyoCommand("myotus")
public final class RootCommand {
}

@MyoCommand(value = "mods", parent = RootCommand.class)
public final class ModsCommand {
}

• value is the literal Brigadier node name
• parent controls where the node is attached
• void.class means the node is a root command

@MyoExecute

Marks the static method to run when the node executes.

@MyoExecute
public static int execute(CommandSourceStack source) {
    return 1;
}

Important rules from CommandRegistrar:

• the method must be static
• the return type is expected to be int
• execution failures are logged and return 0

@MyoArgument

Marks a method parameter that should become a Brigadier argument.

@MyoExecute
public static int execute(CommandSourceStack source, @MyoArgument("enabled") boolean enabled) {
    return 1;
}

Parameters without @MyoArgument are only accepted when they are one of the context types:

• CommandContext
• CommandSourceStack

Supported parameter types

The current registrar maps only a small set of Java types to Brigadier argument types:

Java type	Brigadier argument
int / Integer	IntegerArgumentType.integer()
boolean / Boolean	BoolArgumentType.bool()
String	StringArgumentType.string()
ServerPlayer	EntityArgument.player()
Entity	EntityArgument.entity()

If you use any other parameter type, registration logs an error and the node does not get a valid argument mapping.

Subcommand layout

Myotus supports two subcommand patterns:

• nested command classes declared inside another command class
• separate top-level classes whose parent points at the desired parent node

CommandRegistrar checks both patterns, so you can choose whichever layout is easier to maintain.

Minimal example

@MyoCommand("myotus")
public final class RootCommand {
}

@MyoCommand(value = "set-flag", parent = RootCommand.class)
public final class SetFlagCommand {
    @MyoExecute
    public static int execute(CommandSourceStack source, @MyoArgument("enabled") boolean enabled) {
        source.sendSuccess(() -> Component.literal("enabled=" + enabled), false);
        return 1;
    }
}

That pattern matches how the built-in /myotus mods command is authored.

Practical limitations

• There is no automatic support for optional arguments.
• String parameters use plain string() parsing, not a greedy string variant.
• Validation errors are runtime-logged, not compile-time enforced.
• Discovery is annotation-based, so forgetting @MyoCommand means the class is invisible to the registrar.